Wet processing apparatus, wet processing method and storage medium

ABSTRACT

A wet processing apparatus for wet-processing substrates can suppress the reduction of throughput when some component part thereof becomes unserviceable. The wet processing apparatus includes a first nozzle unit and a second nozzle unit. When the wet processing apparatus operates in a normal mode, a substrate carrying mechanism is controlled so as to deliver substrates alternately to processing units of a first group and those of a second group so that the substrates are processed sequentially in order. When the processing units of the first group (the second group) are unserviceable due to the inoperativeness of the substrate holders, a processing liquid supply system or a nozzle support mechanism, the nozzle unit for the processing units of the second group (the first group) is moved to process substrates by the serviceable ones of the first group (the second group).

BACKGROUND OF THE INVENTION

1. Technical Field

The present disclosure relates to a wet processing apparatus whichprocesses substrates by a wet process that uses a processing liquid, awet processing method, and a storage medium.

2. Description of the Related Art

A photoresist pattern forming process, which is one of semiconductordevice fabricating processes, coats a surface of a semiconductor wafer(hereinafter referred to as “wafer”), namely, a substrate, with a resistfilm, exposes the resist film in a desired pattern, and then developsthe exposed resist film to form a photoresist pattern. Usually, thephotoresist forming process is carried out by a photoresist patternforming system built by combining a coating and developing system, whichcoats a wafer with a resist film and develops the resist film afterexposure, and an exposure system.

The coating and developing system is provided with various kinds of wetprocessing apparatuses. The wet processing apparatus is, for example, aresist solution application apparatus which coats a wafer with a resistsolution. The resist solution application apparatus is provided withresist solution application units. Each resist solution application unitis provided with a wafer holder, a splash cup surrounding a wafer heldby the wafer holder to stop the splashed resist solution, and such.

The resist solution application apparatus is provided with a nozzle headfor pouring a resist solution onto a wafer W. The nozzle head issupported on a support arm to form a nozzle unit. A nozzle unitmentioned in JP-A 2010-045185 is used by a plurality of resist solutionapplication units, for example, three resist solution application units,in common. The nozzle unit moves from one to another of the resistsolution application units to pour a resist solution onto a wafer W heldby the wafer holder. Developing devices which process a wafer w by adeveloping process are the same in construction as the resist solutionapplication units, except that the resist solution application units andthe developing devices use different processing solutions, respectively,for processing wafers W.

The respective numbers of the resist solution application units and thenozzle units are different. Therefore, plurality of resist solutionapplication units cannot process wafers if processing solution supplylines for carrying a processing solution to the nozzle unit are stoppedfor maintenance or if the nozzle unit cannot operate due to trouble.When a resist solution pouring time for which the resist solution ispoured onto a wafer in a normal processing process is long, the nozzleunit needs to be kept for a long time at one resist solution applicationunit, and hence the start of other resist solution application units isdelayed. Consequently, the throughput of the wet processing apparatus islow. Accordingly, there has been a demand for a resist solutionapplication apparatus capable of executing a normal wafer processingprocess at a high throughput and of suppressing the reduction ofthroughput when components thereof malfunction or needs maintenance.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present disclosure to provide a wetprocessing apparatus for processing substrates by a wet process, capableof suppressing the reduction of throughput when a component part thereofbecomes unserviceable, a wet processing method, and a storage medium.

A wet processing apparatus according to the present disclosure forprocessing substrates by pouring a processing solution supplied by aprocessing solution supply system onto the substrates, includes: 2n (nis an integer not smaller than 2) processing units arranged in a lateralrow, including 2n substrate holders for supporting a substrate in ahorizontal position and 2n splash cups respectively surrounding thesubstrate holders, and divided into a first group of the n processingunits on the left side and a second group of the n processing units onthe right side; a first nozzle unit to be used exclusively for the nprocessing units of the first group in a normal processing mode; a firstnozzle support mechanism supporting the first nozzle unit and capable oflaterally moving the first nozzle unit to all the 2n processing units; asecond nozzle unit to be used exclusively for the n processing units ofthe second group in a normal processing mode; a second nozzle supportmechanism supporting the second nozzle and capable of laterally movingthe second nozzle unit to all the 2n processing units; a substratecarrying mechanism for transferring a substrate to and receiving asubstrate from the substrate holders; and a controller which providescontrol signals for controlling the substrate carrying mechanism todeliver substrates alternately to the processing unit of the first groupand that of the second group so as to use the processing units of thefirst and the second group in order in a normal processing mode, and formoving the first nozzle unit for the processing units of the first groupto use the first nozzle unit for processing substrates by theserviceable ones of the processing units of the second group when theprocessing unit of the second group becomes unable to process substratesdue to the inoperativeness of the substrate holder, the processingsolution supply system or the nozzle support mechanism or for moving thesecond nozzle unit for the processing units of the second group to usethe second nozzle unit for processing substrates by the serviceable onesof the processing units of the first group when the processing unit ofthe first group becomes unable to process substrates due to theinoperativeness of the substrate holder, the processing solution supplysystem or the nozzle support mechanism.

The controller may provide a control signal to move the first nozzleunit to use the first nozzle unit for processing substrates by theprocessing units of the second group specified by the operator or tomove the second nozzle unit to use the second nozzle unit for processingsubstrates by the processing units of the first group specified by theoperator when the processing unit of the first group is unable toprocess substrates. The controller may provide a control signal to movethe first nozzle unit to use the first nozzle unit for processingsubstrates by the processing units of the second group previouslyspecified according to the state when the processing unit of the secondgroup is unable to process substrates or to move the second nozzle unitto use the second nozzle unit for processing, substrates by theprocessing units of the first group previously specified according tothe state when the processing unit of the first group is unable toprocess substrates.

The controller may choose a manual mode or an automatic mode when eitherthe processing unit of the first group or that of the second groupbecomes unable to process substrates.

For example, the controller provides a control signal to move the firstnozzle unit to use the first nozzle unit for processing substrates bythe processing units of the second group specified by the operator or tomove the second nozzle unit to use the second nozzle unit for processingsubstrates by the processing units of the first group specified by theoperator when the manual mode is chosen, and the controller provides acontrol signal to move the first nozzle unit to use the first nozzleunit for processing substrates by the processing units of the secondgroup previously specified according to the state or to move the secondnozzle unit to use the second nozzle unit for processing substrates bythe processing units of the first group previously specified accordingto the state when the automatic mode is chosen.

A wet processing method according to the present disclosure to becarried out by a wet processing apparatus for processing substrates bypouring a processing liquid supplied by a processing liquid supplysystem onto the substrates, including 2n (n is an integer not smallerthan 2) processing units arranged in a lateral row, including 2nsubstrate holders for supporting a substrate in a horizontal positionand 2n splash cups respectively surrounding the substrate holders, anddivided into a first group of the n processing units on the left sideand a second group of the n processing units on the right side, a firstnozzle unit to be used exclusively for the n processing units of thefirst group in a normal processing mode, a first nozzle supportmechanism supporting the first nozzle unit and capable of moving thefirst nozzle unit to all the 2n processing units, a second nozzle unitto be used exclusively for processing substrates by the n processingunits of the second group in a normal processing mode, a second nozzlesupport mechanism supporting the second nozzle unit and capable ofmoving the second nozzle unit to all the 2n processing units, asubstrate carrying mechanism for transferring a substrate to andreceiving a substrate from the substrate holders; includes the steps of:pouring the processing liquid through the first nozzle unit ontosubstrates supported on the substrate holders of the processing units ofthe first group in a normal processing mode; pouring the processingliquid through the second nozzle unit onto substrates supported on thesubstrate holders of the processing units of the second group in thenormal processing mode; transferring substrates alternately to theprocessing unit of the first group and that of the second group so as touse the processing units of the first and the second group in order; andlaterally moving the first nozzle unit for the processing units of thefirst group to use the first nozzle unit for processing substrates bythe serviceable ones of the processing units of the second group whenthe substrate holder, the processing liquid supply system or the nozzlesupport mechanism is unserviceable or laterally moving the second nozzleunit for the processing units of the second group to use the secondnozzle unit for processing substrates by the serviceable ones of theprocessing units of the first group when the substrate holder, theprocessing liquid supply system or the nozzle support mechanism isunserviceable.

The substrate processing method may further include the step of movingthe first nozzle unit to use the first nozzle unit for processingsubstrates by the processing units of the second group specified by theoperator when the processing unit of the second group is unable toprocess substrates or moving the second nozzle unit to use the secondnozzle unit for processing substrates by the processing units of thefirst group specified by the operator when the processing unit of thefirst group is unable to process substrates. The wet processing methodmay further include the step of moving the first nozzle unit to use thefirst nozzle unit for processing substrates by the processing units ofthe second group previously specified according to the state when theprocessing unit of the second group is unable to process substrates ormoving the second nozzle unit to use the second nozzle unit forprocessing substrates by the processing units of the first grouppreviously specified according to the state when the processing unit ofthe first group is unable to process substrates.

A storage medium according to the present disclosure stores computerprograms including sets of instructions to be executed by a substrateprocessing apparatus for processing substrates by a wet process in thesteps of the foregoing wet processing method.

According to the present disclosure, the first nozzle unit for theprocessing units of the first group is used for processing substrates bythe serviceable ones of the processing units of the second group whenthe processing unit of the second group becomes unable to processsubstrates or the second nozzle unit for the processing units of thesecond group is used for processing substrates by the serviceable onesof the processing units of the first group when the processing unit ofthe first group becomes unable to process substrates. Thus, thereduction of the throughput of the wet processing apparatus can besuppressed when the wet processing apparatus needs maintenance or somecomponent part of the wet processing apparatus malfunctions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a resist solution application apparatusin a preferred embodiment according to the present disclosure;

FIG. 2 is a plan view of the resist solution application apparatus shownin FIG. 1;

FIG. 3 is a longitudinal sectional view of the resist solutionapplication apparatus shown in FIG. 1;

FIG. 4 is a front elevation of a nozzle unit included in the resistsolution application apparatus;

FIG. 5 is a block diagram of a controller included in the resistsolution application apparatus shown in FIG. 1;

FIG. 6 is a flow diagram of assistance in explaining a setting operationusing an operating panel by way of example;

FIG. 7 is a view of assistance in explaining a memory included in thecontroller;

FIG. 8 is a flow diagram illustrating wafer carrying operations of theresist solution application apparatus shown in FIG. 1 and operations ofthe nozzle units;

FIG. 9 is a flow diagram illustrating operations of wafer carryingoperations of the resist solution application apparatus shown in FIG. 1and operations of the nozzle units;

FIG. 10 is a flow diagram illustrating wafer carrying operations of theresist solution application apparatus shown in FIG. 1 and operations ofthe nozzle units;

FIG. 11 is a flow diagram illustrating wafer carrying operations of theresist solution application apparatus shown in FIG. 1 and operations ofthe nozzle units;

FIG. 12 is a flow diagram illustrating wafer carrying operations of theresist solution application apparatus shown in FIG. 1 and operations ofthe nozzle units;

FIG. 13 is a flow diagram illustrating wafer carrying operations of theresist solution application apparatus shown in FIG. 1 and operations ofthe nozzle units; and

FIG. 14 is a flow diagram illustrating wafer carrying operations of theresist solution application apparatus shown in FIG. 1 and operations ofthe nozzle units.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A resist solution application apparatus 1, namely, a wet processingapparatus, in a preferred embodiment according to the present disclosurewill be described with reference to a perspective view and a plan viewof the resist solution application apparatus 1 shown in FIGS. 1 and 2,respectively. The resist solution application apparatus 1 has a base 31,and four resist solution application units 11 a, 11 b, 11 c and 11 darranged in a lateral row on the base 31.

The resist solution application units 11 a to 11 d are the same inconstruction, and hence the resist solution application unit 11 a willbe described by way of example with reference to a longitudinalsectional view shown in FIG. 3. The resist solution application unit 11a has a spin chuck 12 a provided with a shaft 13 a, namely, a substrateholder for holding a wafer W thereon by attracting a central part of thewafer W by suction, and a rotational driving mechanism 14 a interlockedwith the shaft 13 a. The rotational driving mechanism 14 a drives thespin chuck 12 a holding a wafer W for rotation about a vertical axis.The rotational driving mechanism 14 a is controlled by control signalsprovided by a controller 90 to rotate the spin chuck 12 a at a desiredrotating speed. The rotational driving mechanism 14 a gives thecontroller 90 a signal indicating the rotating speed of the spin chuck12 a.

A splash cup 21 a having an open upper end surrounds the spin chuck 12 aand a wafer W held by the spin chuck 12 a. A sump 23 a having the shapeof a U-shaped annular groove forms the bottom of the splash cup 21 a.The interior of the sump 23 a is divided into an outer annular space andan inner annular space by a partition wall 24 a. The outer and the innerannular space extend outside a circle under the circumference of a waferW held by the spin chuck 12 a. A drain port 25 a is formed in a part ofthe bottom wall of the sump 23 a corresponding to the outer annularspace, Exhaust ports 26 a for exhausting a processing atmosphere isformed in parts of the bottom wall of the sump 23 a corresponding to theinner annular space. Three lifting pins 15 a capable of being verticallymoved are arranged in the splash cup 21 a. Only the two lifting pins 15a are shown in FIG. 3 for convenience. A lifting mechanism 16 a movesthe lifting pins 15 a vertically according to the operation of asubstrate carrying mechanism 10 for carrying a wafer W to the resistsolution application apparatus 1. A wafer W is transferred between thesubstrate carrying mechanism 10 and the spin chuck 12 a by verticallymoving the lifting pins 15 a.

In the drawings, parts of the resist solution application units 11 b, 11c and 11 d corresponding to those of the resist solution applicationunit 11 a are designated by the same numerals with suffixes b, c and d.

Two nozzle units 4 and 5 are installed on the base 31. The nozzle units4 and 5 are the same in construction, and hence the nozzle unit 4 willbe described by way of example. The nozzle unit 4 includes a nozzlesupport mechanism 41, a composite nozzle head 33, and an arm 32supporting the composite nozzle head 32. The nozzle support mechanism 41moves along a guide 42 extended parallel to the row of the resistsolution application units 11 a to 11 d on the base 31. The lateralmovement of the nozzle support mechanism 41 along the guide 42 iscontrolled by control signals provided by the controller 90. The nozzlesupport mechanism 41 sends a position signal indicating a positionthereof with respect to the lateral direction to the controller 90.

The arm 32 extends in a horizontal plane from the nozzle supportmechanism 41 in a direction perpendicular to the moving direction of thenozzle support mechanism 41. The composite nozzle head 33 has, forexample, nine resist solution pouring nozzles 34 and one thinnerspouting nozzle 35. Thinner is a wettability improving liquid forimproving the wettability of the surface of a wafer W. The resistsolution pouring nozzles 34 and the thinner spouting nozzle 35 arearranged in a row parallel to the lateral row of the resist solutionapplication units 11 a to 11 d on a free end part of the arm 32. Theresist solution pouring nozzles 34 and the thinner spouting nozzle 35move above a lateral line passing the centers of wafers W held on thespin chucks 12 a to 12 d of the resist solution application units 11 ato 11 d.

The nozzle unit 5 has a nozzle support mechanism 51 corresponding to thenozzle support mechanism 41. The nozzle support mechanism 51 moves alonga guide 52 laid parallel to the lateral row of the resist solutionapplication units 11 a to 11 d on the base 31. Thus, the nozzles of thenozzle unit 5, similarly to those of the nozzle unit 4, can pour theresist solution and the thinner onto wafers W held by the spin chucks 12a to 12 d of the resist solution application units 11 a to 11 d.

Indicated at 36 in FIG. 3 is a processing liquid supply unit. Theprocessing liquid supply unit 36 has processing liquid supply mechanisms37 each including a resist solution tank containing a resist solution tobe supplied to the resist solution pouring nozzles 34 and apressurization device for pressurizing the resist solution tank, and aprocessing liquid supply mechanism 37 including a thinner tankcontaining the thinner to be supplied to the thinner spouting nozzles 35and a pressurization device for pressurizing the thinner tank to supplythe thinner to the thinner spouting nozzles 35. The number of theprocessing liquid supply mechanisms 37 is ten which is equal to thenumber of the resist solution pouring nozzles 34 and the thinnerspouting nozzle 35 of each of the nozzle unit 4 and 5. The resistsolution tanks of the processing liquid supply mechanisms 37 containresist solutions respectively having different resist concentrations.Thus, a resist solution of a desired resist concentration can be pouredonto a wafer W.

Indicated at 38 in FIG. 3 are processing liquid supply lines connectingthe nozzles 34 and 35 to the processing liquid supply mechanisms 37. Aflow controller 30 including valves 39 is placed in the processingliquid supply lines 38. The controller 90 provides control signals foropening and closing the valves 39 to pour the nine kinds of resistsolutions and the thinner selectively onto wafers W held by therespective spin chucks 12 a to 12 d of the resist solution applicationunits 11 a to 11 d.

Referring to FIGS. 1 and 2, nozzle baths 6 and 7 are disposed near theopposite ends of the row of the resist solution application units 11 ato 11 d. The nozzle bath 6 is a cup having an open upper end. A space inthe nozzle bath 6 is used as a waiting space 61 for holding thecomposite nozzle head 33 of the nozzle unit 4 therein. The nozzle bath 7is the same in construction as the nozzle bath 6 and defines a waitingspace 71 corresponding to the waiting space 61. The waiting space 71holds the composite nozzle head 33 of the nozzle unit 5 therein. Thecomposite nozzle heads 33 of the nozzle units 4 and 5 are held in thewaiting spaces 61 and 71, respectively, when the resist solutions andthe thinner do not need to be poured onto wafers W. The nozzle bath 6will be described by way of example with reference to FIG. 4.

The nozzle bath 6 is provided with an optical sensor including a lightprojector 62 and a light receiver 63 the light receiver 63 sends out asignal corresponding to the amount of light received from the lightprojector 62 to the controller 90. When the composite nozzle head 33 isheld in the waiting space 61 as shown in FIG. 4, light projected by thelight projector 62 is intercepted by the composite nozzle head 33 andthe output signal of the light receiver 63 changes. The controller 90decides whether or not the composite nozzle head 33 is held in thewaiting space 61 on the basis of the level of the output signal of thelight receiver 63. The nozzle bath 6 is provided with a drain port 64.In some cases, the processing liquids are spouted through the nozzles 34and 35 for maintenance while the composite nozzle head 33 is held in thewaiting space 61. When the processing liquids are thus spouted, depositsin the nozzles 34 and 35 and the processing liquid supply lines 38 areremoved to clean the processing liquid supply lines. The processingliquids used for cleaning are drained through the drain port 64.

Referring again to FIGS. 1 and 2, the resist solution applicationapparatus 1 is provided with four edge removing mechanisms 8 forremoving an edge part of a resist film formed on a wafer W by each ofthe resist solution application units 11 a to 11 d to prevent the resistfilm from coming off the wafer W. Each of the edge removing mechanisms 8is provided with a solvent spouting nozzle 81 for spouting a solventcapable of dissolving the resist film onto a wafer W. The nozzle 81 issupported by a support arm 82. A driving mechanism 83 moves the supportarm 82 supporting the solvent spouting nozzle 81 vertically. The drivingmechanisms 83 move along guides 84 in directions parallel to the lateralrow of the resist solution application units 11 a to 11 d. Nozzle baths85 each having an open upper end are disposed beside the splash cups 21a to 21 d, respectively. The driving mechanism 83 moves the solventspouting nozzle 81 between a waiting space 86 defined by the nozzle bath85 and a spouting position above the edge of a wafer W held inside thesplash cup 21.

A resist solution application process for applying the resist solutionto a wafer W to be executed by the resist solution application apparatus1 will be described. The resist solution application units 11 a to 11 dprocess wafers W by the same resist solution application process. Theresist solution application units 11 a to 11 d carries out the resistsolution application process in a parallel execution mode. Normally,wafers W are delivered to the resist solution application units 11 a to11 d. The nozzle units 4 and 5 are used for processing wafers W by theresist solution application units 11 a and 11 b and for processingwafers W by the resist solution application units 11 c and 11 d,respectively. A processing procedure for processing a wafer W deliveredto the resist solution application unit 11 a using the nozzle unit 4 bythe resist solution application process will be described by way ofexample.

The substrate carrying mechanism 10 carries a wafer W to a positionabove the splash cup 21 a. Then, the lifting pins 15 a transfers thewafer W to the spin chuck 12 a such that the wafer W is held by itscentral part by the spin chuck 12 a. Subsequently, the wafer W isrotated at a predetermined rotating speed about a vertical axis, and thecomposite nozzle head 33 is moved from the nozzle bath 6 to a positionabove the wafer W such that the thinner spouting nozzle 35 is located ata position directly above the center of the wafer W and at apredetermined height from the wafer W. Then, the thinner is spoutedthrough the thinner spouting nozzle 35 onto a central part of the waferW.

After stopping spouting the thinner, the resist solution pouring nozzle34 is located above a central part of the wafer W, and then the resistsolution is poured onto the central part of the wafer W. The resistsolution is spread radially outward by centrifugal force to spread thethinner wetting the surface of the wafer W toward the edge of the waferW. Thus, the resist solution is spread all over the surface of the waferW by a spin-coating effect. The composite nozzle head 33 of the nozzleunit 4 is returned to the waiting space 61 in the nozzle bath 6 afterstopping pouring the resist solution. Subsequently, the solvent spoutingnozzle 81 is moved from the nozzle bath 85 to a position above the edgeof the wafer W and the thinner is spouted through the solvent spoutingnozzle 81 to remove part of a resist film from a circumferential part ofthe surface of the wafer W. Then, the solvent pouring nozzle 81 isreturned to the nozzle bath 85, the lifting pins 15 a transfer the waferW to the substrate carrying mechanism 10, and then the wafer W iscarried out from the resist solution application apparatus 1.

The controller 90 included in the resist solution application apparatus1 will be described with reference to FIG. 5. The controller 90 has aCPU 91, a memory 92 and programs 93. Components of the controller 90 areconnected to a bus 94. The programs 93 are sets of instructionscommanding the controller 90 to send control signals to the componentsof the resist solution application apparatus 1 to carry out the resistsolution application process. The controller 90 controls wafer rotatingoperations of the rotational driving mechanisms 14 a to 14 d forrotating a wafer W, wafer transfer operations of the lifting pins 15 ato 15 d for transferring a wafer W, carrying operations of the substratecarrying mechanism 10 for carrying a wafer W, operations of the nozzlesupport mechanisms 41 and 51 for moving the nozzle units 4 and 5, andoperations of the flow controller 30 for controlling operations forpouring the resist solution and the thinner onto a wafer W. The programs93 including instructions commanding operations for entering processparameters and displaying information are stored in a storage medium,such as a flexible disk, a compact disk, a hard disk, a magnetoopticaldisk or a memory card, and the storage medium is installed in thecontroller 90.

The controller 90 has an operating panel 95, such as a touch panel. Theoperator of the resist solution application apparatus 1 decides acomponent part of the resist solution application apparatus 1 to beunused for maintenance or a component part of the resist solutionapplication apparatus 1 malfunctioning due to trouble or an accident byoperating the operating panel 95. Then, the resist solution applicationunits 11 to which wafers W are delivered automatically and the nozzleunit to be used in the normal operating state are changed according tothe foregoing decision. The operator can manually change the resistsolution application units 11 to which wafers W are to be delivered andthe nozzle unit to be used by operating the operating panel 95.

FIG. 6 shows information displayed on the operating panel 95 by way ofexample. The operator can enter a component part that needs maintenanceamong the nozzle units 4 and 5 and the resist solution application units11 a to 11 d by operating a first picture 95 a displayed on theoperating panel 95. When the nozzle units 4 and 5 are entered ascomponent parts that need maintenance, an operation for cleaning theprocessing liquid supply lines by spouting the processing liquid in thewaiting spaces 61 and 71 or maintenance work for changing othercomponent parts is entered in the first picture 95 a.

The operator can change the first picture 95 a for a second picture 95b. The operator can enter a component part among the nozzle units 4 and5 and the resist solution application units 11 a to 11 d as a faultycomponent part by operating the second picture 95 b. FIG. 7 shows thememory 92. The component part that needs maintenance entered byoperating the first picture 95 a and the faulty component part enteredby operating the second picture 95 b are stored in the memory 92.

The operator can change the second picture 95 b for a third picture 95c. When the component part that needs maintenance is entered byoperating the first picture 95 a, the second picture 95 b is notdisplayed and the third picture 95 c is displayed. The operator canchoose either an automatic or a manual selection mode for choosing theresist solution application units 11 for which the nozzle units 4 and 5operate by operating the third picture 95 c. When the automaticselection mode is chosen, the program 93 decides the resist solutionapplication units 11 to which wafers W are to be automatically deliveredand the nozzle unit to be used, on the basis of the component part thatneeds maintenance and the faulty component part stored in the memory 92.When the manual selection mode is chosen by operating the third picture95 c, a fourth picture 95 d is displayed on the operating panel 95. Theoperator can enter the resist solution application units 11 for whichthe nozzle units 4 and 5 are to be used in the fourth picture 95 d.

In the following description, wafers W are designated by the letters ofthe Latin alphabet A. B, C and such indicating lots and numeralsindicating numerical order in which wafers W of each lot are carriedinto the resist solution application apparatus 1 and suffixed onto theletters indicating lots. For example, a wafer W of a lot A to be carriedthird into the resist solution application apparatus 1 is designated byA3, and a wafer W of a lot next to the lot A to be carried fifth intothe resist solution application apparatus 1 is designated by B5.

FIG. 8 shows, in a time series, operations of the substrate carryingmechanism 10 for carrying wafers A1 to A8 to the resist solutionapplication units 11 a to 11 d. The arrows in an upper part of FIG. 8define ranges in which the nozzle units 4 and 5 move, respectively. Afirst group G1 includes the resist solution application units 11 a and11 b, and a second group G2 includes the resist solution applicationunits 11 c and 11 d. Wafers A1 to A8 are delivered alternately to thefirst group G1 and the second group G2. Wafers A1 to A8 are deliveredalternately to the resist solution application units of each of thefirst group G1 and the second group G2. More concretely, wafers A1, A2,A3 and A4 are delivered sequentially to the resist solution applicationunits 11 a, 11 c, 11 b and 11 d, respectively. The nozzle unit 4 is usedfor processing the wafers A1, A3, A5 and A7 delivered to the resistsolution application units 11 a and 11 b, and the nozzle unit 5 is usedfor processing the wafers A2, A4, A6 and A8 delivered to the resistsolution application units 11 c and 11 d.

Manners of carrying wafers W and using the nozzle units 4 and 5 in casessome component part of the resist solution application apparatus 1 needsmaintenance or malfunctions. In the following cases, it is supposed thatthe operator operates the operating panel 95 to choose the automaticselection mode for selecting the resist solution application units 11for which the nozzle units 4 and 5 are to be used.

Case 1: The Nozzle Unit 4 Needs Maintenance and the Processing LiquidSupply Lines Need Cleaning.

When the foregoing condition for Case 1 is determined, wafers W of thelot A in process in the resist solution application apparatus 1 areprocessed in the normal processing mode. After all the wafers Ai (i=1, 2. . . , n) of the lot A have been processed, the nozzle unit 4discharges the processing liquids in the waiting space 61 of the nozzlebath 6 to clean the processing liquid supply lines. Meanwhile, wafers Bi(i=1, 2, . . . , n) of the lot B are carried alternately to the resistsolution application units 11 c and 11 d, and the nozzle unit 5 is usedfor processing the wafers Bi of the lot B as shown in FIG. 9. Aftermaintenance work has been completed, the normal wafer processingoperation is resumed to process wafers W of the next lot by using thenozzle units 4 and 5 and the resist solution application units 11 a to11 d.

Case 2: The Nozzle Unit 4 Needs Maintenance and the Processing LiquidSupply Lines do not Need Cleaning.

When the foregoing condition for Case 2 is determined, wafers W of thelot A in process in the resist solution application apparatus 1 areprocessed in the normal processing mode. After all the wafers Ai of thelot A have been processed, the composite nozzle head 33 of the nozzleunit 4 is held in the waiting space 61 of the nozzle bath 6. Wafers Biof the lot B are carried sequentially to the resist solution applicationunits 11 a to 11 d in normal order as shown in FIG. 10, and only thenozzle unit 5 is used for processing the wafers Bi of the lot B. Whilethe wafers Bi of the lot B are in process, the operator carries outmaintenance work for changing parts of the nozzle unit 4 and such. Afterthe maintenance has been completed, the operator operates the operatingpanel 95 to determine predetermined conditions, and then the normalwafer processing operation is resumed to process wafers W of the nextlot.

The resist solution application units 11 a and 11 b are not used in Case1 to prevent the mist of the processing liquids discharged into thenozzle bath 6 from adhering to wafers W being processed by the resistsolution application units 11 a and 11 b adjacent to the nozzle bath 6.In Case 2, all the resist solution application units 11 a to 11 d areused to enhance throughput by processing wafers W by the parallelprocessing operations of the resist solution application units.

If a decision that the nozzle unit 5 needs maintenance is made insteadof the decision that the nozzle unit 4 needs maintenance in Case 1, thenozzle units 4 and the resist solution application units 11 a and 11 bare used for processing wafers W. If a decision that the nozzle unit 5needs maintenance is made instead of the decision that the nozzle unit 4needs maintenance in Case 2, the nozzle units 4 and the resist solutionapplication units 11 a to 11 d are used for processing wafers W.

Case 3: The Nozzle Unit 4 is Malfunctioning.

When the foregoing condition for Case 3 is decided, the controller 90stops the nozzle unit 4 and decides whether or not the composite nozzlehead 33 of the nozzle unit 4 is held in the waiting space 61. If thecomposite nozzle head 33 of the nozzle unit 4 is in a range outside thewaiting space 61, wafers W are carried alternately to the resistsolution application units 11 c and 11 d and only the nozzle unit 5 isused for processing the wafers Ai of the lot A. In FIG. 11, amalfunctioning component part is decided after a wafer A5 has beendelivered to the resist solution application unit 11 a, a wafer A6 andthe flowing wafers are delivered to the resist solution applicationunits 11 c and 11 d, and the nozzle unit 5 is used for processing thosewafers.

When the controller 90 decides that the composite nozzle head 33 of thenozzle unit 4 is held in the waiting space 61, the respectivedestinations of wafers W are not changed and the wafers W are deliveredto the resist solution application units 11 a to 11 d in normal order.After this decision has been made, the wafers W delivered to the resistsolution application units 11 a to 11 d are processed by using thenozzle unit 5. FIG. 12 shows, by way of example, a state where amalfunctioning component part is decided and the foregoing decision ismade after the wafer A5 has been delivered to the resist solutionapplication unit 11 a, and the wafer A6 and the following wafers areprocessed by using the nozzle unit 5. In case 3, the normal waferprocessing operation for processing wafers W of the next lot is resumedafter the operator has entered predetermined conditions by operating theoperating panel 95.

Wafers W are processed by the resist solution application units 11 c and11 d when the nozzle unit 4 is stopped with the composite nozzle head 33positioned in a range outside the waiting space 61 to avoid collisionbetween the nozzle units 4 and 5. Since the nozzle units 4 and 5 do notcollide with each other when the nozzle unit 4 is stopped with thecomposite nozzle head 33 positioned in the waiting space 61, it isexpedient to use all the resist solution application units 11 a to 11 dfor suppressing the reduction of throughput.

When a decision that the nozzle unit 5 is malfunctioning is made insteadof the decision that the nozzle unit 4 is malfunctioning in Case 3, thedestinations of wafers W are dependent on a position where the nozzleunit 5 is stopped. If the nozzle unit 5 is stopped with its compositenozzle head 33 in a range outside the waiting space 71, wafers W aredelivered alternately to the resist solution application units 11 a and11 b, and the nozzle unit 4 is used for processing the wafers W. If thenozzle unit 5 is stopped with its composite nozzle head 33 held in thewaiting space 71, wafers W are delivered to all the resist solutionapplication units 11 a to 11 d in a normal delivery mode and the nozzleunit 4 is used for processing the wafers W delivered to the resistsolution application units 11 a to 11 d.

Case 4: A Decision that the Resist Solution Application Unit 11 a isFaulty is Made.

When a decision that the resist solution application unit 11 a is faultyis made, the substrate carrying mechanism 10 delivers wafers W of thelot A to be carried into the resist solution application apparatus 1sequentially to the resist solution application units 11 b to 11 d inorder of completion of processing wafers W. Thereafter, wafers W of thelot A are delivered repeatedly in that order to the resist solutionapplication units 11 b to 11 d. The nozzle unit 4 is used for processingwafers W by the resist solution application unit 11 b, and the nozzleunit 5 is used for processing wafers W by the resist solutionapplication units 11 c and 11 d. An upper drawing in FIG. 13 illustratesa mode of sequential delivery of wafers A6 to A13 to the resist solutionapplication units 11 b to 11 d when the foregoing decision is made aftera wafer A6 has been delivered to the resist solution application unit 11c.

After operations for processing all the wafers Ai of the lot A have beencompleted, the composite nozzle head 33 of the nozzle unit 4 is held forwaiting in the waiting space 61. As illustrated in a lower drawing shownin FIG. 13, wafers Bi of the next lot B are delivered to the resistsolution application units 11 b to 11 d in the same sequence as that inwhich the wafers Ai of the lot A were delivered to the resist solutionapplication units 11 b to 11 d. The nozzle unit 5 is used for processingthe wafers Bi of the lot B delivered to the resist solution applicationunits 11 b to 11 d. The operator repairs the resist solution applicationunit 11 a while the wafers Bi of the lot B are being processed. In Case4, the normal wafer processing operation for processing the wafers W ofthe next lot is resumed after the operator has entered predeterminedconditions by operating the operating panel 95.

As mentioned above, neither the composite nozzle head 33 of the nozzleunit 4 nor that of the nozzle unit 5 moves over the resist solutionapplication unit 11 b while the wafers Bi of the lot B are beingprocessed and the composite nozzle head 33 of the nozzle unit 4 is heldin the waiting space 61. Therefore, the operator can access and repairthe resist solution application unit 11 a without being interfered withby the nozzle units 4 and 5. Since the nozzle unit 5 is used forprocessing the wafers Bi of the lot B while the resist solutionapplication unit 11 a is under repair, the reduction of throughput dueto the interruption of using the nozzle unit 4 can be suppressed.

In Case 4, the same operations as those executed when the resistsolution application unit 11 a is under repair are executed when theresist solution application unit 11 d at the opposite end of the row ofthe resist solution application units 11 a to 11 d is faulty. Moreconcretely, wafers W are delivered to the resist solution applicationunits 11 a to 11 c, and the composite nozzle head 33 of the nozzle unit5 is held in the waiting space 71. An example of trouble in one of theresist solution application units 11 a to 11 d is an unserviceable stateof one of the spin chucks 12 a to 12 d due to the malfunction of one ofthe rotational driving mechanisms 14 a to 14 d.

Case 5: A Decision that the Resist Solution Application Unit 11 b isFaulty is Made.

When a decision that the resist solution application unit 11 b is faultyis made, the substrate carrying mechanism 10 delivers wafers W of thelot A succeeding the wafers W in process sequentially to the resistsolution application units 11 a, 11 c and 11 d in order of completion ofprocessing wafers W. Thereafter, wafers W are delivered repeatedly inthat order to the resist solution application units 11 a, 11 c and 11 d.The nozzle unit 4 is used for process the wafers W by the resistsolution application unit 11 a, and the nozzle, unit 5 is used forprocessing wafers W by the resist solution application units 11 c and 11d. FIG. 14 illustrates a mode of sequential delivery of wafers W of thelot A to the resist solution application units 11 a, 11 c and 11 d whenthe foregoing decision is made after a wafer A3 has been delivered tothe resist solution application unit 11 b.

The composite nozzle heads 33 of the nozzle units 4 and 5 do not moveover the resist solution application unit 11 b after the foregoingdecision has been made. Therefore, the operator can access and repairthe resist solution application unit 11 b without being interfered withby the nozzle units 4 and 5. After the repair of the resist solutionapplication unit 11 b has been completed, the operator operates theoperating panel 95 to determine predetermined conditions, and then thenormal wafer processing operation is resumed to process wafers W of thenext lot.

If a decision that the resist solution application unit 11 c needsrepair is made instead of the decision that the resist solutionapplication unit 11 b needs repair in Case 5, operations similar to theforegoing operations are executed. More concretely, wafers W are carriedto the resist solution application units 11 a, 11 b and 11 d. The nozzleunit 4 is used for processing wafers W by the resist solutionapplication units 11 a and 11 b, and the nozzle unit 5 is used forprocessing wafers W by the resist solution application unit 11 d.

Operations similar to, for example, those executed in Cases 4 and 5 areexecuted when a decision that the resist solution application units 11 aand 11 b need maintenance is made in Cases 4 and 5 instead of thedecision that the resist solution application units 11 a and 11 b arefaulty.

If any one of the resist solution application units ha to 11 d of theresist solution application apparatus 1 becomes unserviceable asmentioned above, the nozzle unit that is not used for processing a waferW by the unserviceable resist solution application unit 11 in the normalprocessing mode is used for processing wafers W by the resist solutionapplication unit 11. Thus, the reduction of throughput can be suppressedeven if some component part of the resist solution application apparatus1 needs maintenance or is faulty. Since the two nozzle units 4 and 5 areused for processing wafers W by the resist solution application units 11a to 11 d in the normal processing mode, throughput is high as comparedwith that when a single nozzle unit is used. Even if a resist solutionpouring time is extended, reduction of throughput due to the extensionof resist solution pouring time can be suppressed.

Although the operator decides a faulty component part in the foregoingexamples, a faulty component part may be automatically detected by thecontroller 90 instead of the decision of a faulty component part by theoperator. For example, the controller 90 compares the output rotatingspeeds of the rotational driving mechanisms 14 a to 14 d calculated onthe basis of output signals provided by the rotational drivingmechanisms 14 a to 14 d with a predetermined rotating speed, the resistsolution application unit 11 including the rotational driving mechanism14 is decided to be a faulty component part when the difference betweenthe predetermined rotating speed and the output rotating speed of therotational driving mechanism 14 included in the resist solutionapplication unit 11 is not lower than a predetermined set value, andprocessing operations for Case 4 or 5 are executed automatically.

In another case, the controller 90 determines the respective positionsof the nozzle support mechanisms 41 and 51 on the base 31 with respectto the lateral direction on the basis of output signals provided by thenozzle support mechanisms 41 and 51. The controller 90 calculates thedifference between the duration of transmission of a control signalprovided by the controller 90 for moving the nozzle support mechanism 41to a predetermined position with respect to the lateral direction andthe duration of transmission of an output signal provided by the nozzlesupport mechanism 41 upon the arrival of the nozzle support mechanism 41at the predetermined position, and the difference between the durationof transmission of a control signal provided by the controller 90 formoving the nozzle support mechanism 51 to a predetermined position withrespect to the lateral direction and the duration of transmission of anoutput signal provided by the nozzle support mechanism 51 upon thearrival of the nozzle support mechanism 51 at the predeterminedposition. When the difference is greater than a set value, it is decidedthat the nozzle unit including the nozzle support mechanism that causedthe large difference is a faulty component part, and then the processingoperations for Case 3 are executed automatically.

The wafer carrying operations mentioned in the description of thosecases are only examples, and wafer carrying operations of the presentdisclosure are not limited to those explained by way of example. Forexample, wafers W may be carried to the resist solution applicationunits 11 b to 11 d and the nozzle unit 5 may be used for processingthose wafers W in Case 1.

The processing liquid which is poured through the nozzles of the nozzleunits of the present disclosure is not limited to the resist solutionand may be a developer or a processing liquid for forming antireflectionfilms.

1. A wet processing apparatus for processing substrates by pouring aprocessing liquid supplied by a processing liquid supply system onto thesubstrates, said wet processing apparatus comprising: 2n (n is aninteger not smaller than 2) processing units arranged in a lateral rowand respectively including 2n substrate holders for supporting asubstrate in a horizontal position and 2n splash cups respectivelysurrounding the substrate holders, and divided into a first group of then processing units on the left side and a second group of the nprocessing units on the right side; a first nozzle unit to be usedexclusively for the n processing units of the first group in a normalprocessing mode; a first nozzle support mechanism supporting the firstnozzle unit and capable of laterally moving the first nozzle unit to allthe 2n processing units; a second nozzle unit to be used exclusively forthe n processing units of the second group in a normal processing mode;a second nozzle support mechanism supporting the second nozzle andcapable of laterally moving the second nozzle unit to all the 2nprocessing units; a substrate carrying mechanism for transferring asubstrate to and receiving a substrate from the substrate holders; and acontroller which provides control signals for controlling the substratecarrying mechanism to deliver substrates alternately to the processingunit of the first group and that of the second group so as to use theprocessing units of the first and the second group in order in a normalprocessing mode, and for moving the first nozzle unit for the processingunits of the first group to use the first nozzle unit for processingsubstrates by the serviceable ones of the processing units of the secondgroup when the processing unit of the second group becomes unable toprocess substrates due to the inoperativeness of the substrate holder,the processing solution supply system or the nozzle support mechanism orfor moving the second nozzle unit for the processing units of the secondgroup to use the second nozzle unit for processing substrates by theserviceable ones of the processing units of the first group when theprocessing unit of the first group becomes unable to process substratesdue to the inoperativeness of the substrate holder, the processingsolution supply system or the nozzle support mechanism.
 2. The substrateprocessing apparatus according to claim 1, wherein the controllerprovides a control signal to move the first nozzle unit to use the firstnozzle unit for processing substrates by the processing units of thesecond group specified by the operator or to move the second nozzle unitto use the second nozzle unit for processing substrates by theprocessing units of the first group specified by the operator when theprocessing unit of the first group is unable to process substrates. 3.The wet processing apparatus according to claim 2, wherein thecontroller chooses either a manual mode or an automatic mode when eitherthe processing unit of the first group or that of the second group isunable to process substrates, the controller provides a control signalto move the first nozzle unit to use the first nozzle unit forprocessing substrates by the processing units of the second groupspecified by the operator or to move the second nozzle unit to use thesecond nozzle unit for processing substrates by the processing units ofthe first group specified by the operator when the manual mode ischosen, and the controller provides a control signal to move the firstnozzle unit to use the first nozzle unit for processing substrates bythe processing units of the second group previously specified accordingto the state or to move the second nozzle unit to use the second nozzleunit for processing substrates by the processing units of the firstgroup previously specified according to the state when the automaticmode is chosen.
 4. The wet processing apparatus according to claim 1,wherein the controller provides a control signal to move the firstnozzle unit to use the first nozzle unit for processing substrates bythe processing units of the second group previously specified accordingto the state when the processing unit of the second group is unable toprocess substrates or to move the second nozzle unit to use the secondnozzle unit for processing substrates by the processing units of thefirst group previously specified according to the state when theprocessing unit of the first group is unable to process substrates. 5.The wet processing apparatus according to claim 4, wherein controllerchooses a manual mode or an automatic mode when the processing unit ofthe first group or that of the second group is unable to processsubstrates, the controller provides a control signal to move the firstnozzle unit to use the first nozzle unit for processing substrates bythe processing units of the second group specified by the operator or tomove the second nozzle unit to use the second nozzle unit for processingsubstrates by the processing units of the first group specified by theoperator when the manual mode is chosen, and the controller provides acontrol signal to move the first nozzle unit to use the first nozzleunit for processing substrates by the processing units of the secondgroup previously specified according to the state or to move the secondnozzle unit to use the second nozzle unit for processing substrates bythe processing units of the first group previously specified accordingto the state when the automatic mode is chosen.
 6. A wet processingmethod to be carried out by a wet processing apparatus for processingsubstrates by pouring a processing liquid supplied by a processingliquid supply system onto substrates, including 2n (n is an integer notsmaller than 2) processing units arranged in a lateral row, including 2nsubstrate holders for supporting a substrate in a horizontal positionand 2n splash cups respectively surrounding the substrate holders, anddivided into a first group of the n processing units on the left sideand a second group of the n processing units on the right side; a firstnozzle unit to be used exclusively for processing substrates by the nprocessing units of the first group in a normal processing mode; a firstnozzle support mechanism supporting the first nozzle unit and capable ofmoving the first nozzle unit to all the 2n processing units; a secondnozzle unit to be used exclusively for processing substrates by the nprocessing units of the second group in a normal processing mode; asecond nozzle support mechanism supporting the second nozzle unit andcapable of moving the second nozzle unit to all the 2n processing units;substrate carrying mechanism for transferring a substrate to andreceiving a substrate from the substrate holders; said wet processingmethod comprising the steps of: pouring the processing liquid throughthe first nozzle unit onto substrates supported on the substrate holdersof the processing units of the first group in a normal processing mode;pouring the processing liquid through the second nozzle unit ontosubstrates supported on the substrate holders of the processing units ofthe second group in a normal processing mode; transferring substratesalternately to the processing unit of the first group and that of thesecond group so as to use the processing units of the first and thesecond group in order; and laterally moving the first nozzle unit forthe processing units of the first group to use the first nozzle unit forprocessing substrates by the serviceable ones of the processing units ofthe second group when the substrate holder, the processing liquid supplysystem or the nozzle support mechanism is unserviceable or laterallymoving the second nozzle unit for the processing units of the secondgroup to use the second nozzle unit for processing substrates by theserviceable ones of the processing units of the first group when thesubstrate holder, the processing liquid supply system or the nozzlesupport mechanism is unserviceable.
 7. The wet processing methodaccording to claim 6 further comprising the step of moving the firstnozzle unit to use the first nozzle unit for processing substrates bythe processing units of the second group specified by the operator whenthe processing unit of the second group is unable to process substratesor moving the second nozzle unit to use the second nozzle unit forprocessing substrates by the processing units of the first groupspecified by the operator when the processing unit of the first group isunable to process substrates.
 8. The wet processing method according toclaim 6 further comprising the step of moving the first nozzle unit touse the first nozzle unit for processing substrates by the processingunits of the second group previously specified according to the statewhen the processing unit of the second group is unable to processsubstrates or moving the second nozzle unit to use the second nozzleunit for processing substrates by the processing units of the firstgroup previously specified according to the state when the processingunit of the first group is unable to process substrates.
 9. A storagemedium storing computer programs including sets of instructions to beexecuted by a wet processing apparatus to carry out the substrateprocessing method according to claim 6.